Critical path method
The critical path method (CPM) is an algorithm
In mathematics and computer science, an algorithm is an effective method expressed as a finite list of well-defined instructions for calculating a function. Algorithms are used for calculation, data processing, and automated reasoning...

 for scheduling a set of project activities. It is an important tool for effective project management
Project management
Project management is the discipline of planning, organizing, securing, and managing resources to achieve specific goals. A project is a temporary endeavor with a defined beginning and end , undertaken to meet unique goals and objectives, typically to bring about beneficial change or added value...

The critical path method (CPM) is a project modeling technique developed in the late 1950s by Morgan R. Walker of DuPont
E. I. du Pont de Nemours and Company , commonly referred to as DuPont, is an American chemical company that was founded in July 1802 as a gunpowder mill by Eleuthère Irénée du Pont. DuPont was the world's third largest chemical company based on market capitalization and ninth based on revenue in 2009...

 and James E. Kelley, Jr. of Remington Rand
Remington Rand
Remington Rand was an early American business machines manufacturer, best known originally as a typewriter manufacturer and in a later incarnation as the manufacturer of the UNIVAC line of mainframe computers but with antecedents in Remington Arms in the early nineteenth century. For a time, the...

. Kelley and Walker related their memories of the development of CPM in 1989. Kelley attributed the term "critical path" to the developers of the Program Evaluation and Review Technique
Program Evaluation and Review Technique
The Program ' Evaluation and Review Technique, commonly abbreviated PERT, is a statistical tool, used in project management, that is designed to analyze and represent the tasks involved in completing a given project...

 which was developed at about the same time by Booz Allen Hamilton
Booz Allen Hamilton
Booz Allen Hamilton Inc. , or more commonly Booz Allen, is an American public consulting firm headquartered in McLean, Fairfax County, Virginia, with 80 other offices throughout the United States. Ralph Shrader is its Chairman and Chief Executive Officer. The firm was founded by Edwin Booz in...

 and the US Navy.